Enigmatic hotspot of crayfish diversity at risk: Invasive potential of non-indigenous crayfish if introduced to New Guinea

The large island of New Guinea has a rich indigenous astacofauna represented by numerous parastacids from the genus Cherax. The western half of the island is part of Indonesian territory. Indonesia is known to be the main exporter of ornamental crayfish globally, and certain New Guinean species are exploited as ornamentals within the international pet trade. Moreover, one non-indigenous species has been previously recorded being cultured in Java, Indonesia. This species, the North American Procambarus clarkii, is a vector of crayfish plague, the disease that is lethal to most parastacids. This population has already tested positive for the disease. As the transport of non-indigenous crayfish within the Indonesian territory is not restricted, their introduction to New Guinea can be expected. The Indonesian market was therefore surveyed for ornamental crayfish and their environmental suitability evaluated, as represented by temperature during the drought and rainy seasons in New Guinea. Four North American and one Australian species were found advertised for sale. One of them, P. clarkii, was assessed as the most damaging species, followed by other North American species. A total ban on the culture and transport of the highest risk crayfish species in Indonesia and Papua New Guinea is recommended.